The present invention relates to a ski boot.
The problem of achieving easy entry of the foot and at the same time allowing optimum support for the lower part of the leg during sports practice is currently felt in ski boots.
Ski boots are known in which the rear quarter can adapt to the leg for a certain degree. French patent application No. 7719655, which claims a U.S. priority dated Jul. 12, 1976, discloses a ski boot on whose rear quarter has articulations suitable for allowing its deformation in the direction of the front quarter. However, this solution, despite allowing the rear quarter to follow the shape of the leg during forward flexing, cannot, due to abutments defined on said quarter, follow the natural arcuated shape of the leg or assist it during its backward flexing.
U.S. Pat. No. 4,095,356 discloses a ski boot whose rear quarter has an upper cuff which is pivoted laterally to the front quarter and does not affect the heel region. The rear quarter also has a wing which is pivoted transversely to the shell and affects the heel region.
This solution, too, has problems, because during backward flexing the wing is free to rotate about its own axis and therefore does not support the heel in any way.
Furthermore, during forward flexing, the wing, moved by the upper cuff with which it interacts, exerts considerable localized pressure on the heel, and this creates discomfort for the user.
European Patent No. 0278245 also discloses a ski boot having a device arranged inside the rear quarter and allowing the innerboot to adapt to the lower part of the leg by means of a movement along an axis which is longitudinal to the rear quarter.
This solution only allows to deform the padding of the innerboot and thus merely allows to achieve a static adjustment for adaptation to the anatomical shape of the leg; it does not allow in any way adaptation to, and embracing of, the rear region of the lower part of the leg during sports practice.
U.S. Pat. No. 4,839,973 discloses a ski boot constituted by a quarter which is pivoted laterally to a shell and is also articulated to the rear, about a longitudinal axis, to a cuff which is in turn pivoted laterally to said shell.
Said cuff therefore has no heel supporting function but only allows, by virtue of its articulation to the quarter, to increase the opening of said quarter.
Therefore, this function only has a static aspect and can be used during the insertion or extraction of the foot in or from the boot,
European Patent No. 374056 discloses a rear-entry ski boot wherein the rear quarter is constituted by a cuff, which is pivoted together with the front quarter to the shell at a slot, and by a support, which embraces the heel region, is in turn rigidly associated with the lateral ends of the cuff and is pivoted to the shell in an underlying region.
This solution allows the cuff to rotate with respect to the support, during the opening of the quarters, until it abuts at an adapted protrusion defined on said support.
During skiing, instead, the support is locked with respect to the shell, thus univocally supporting the leg with no possibility of adaptation according to the compression or extension performed during sports practice.
The Italian Patent No. 19382A/81, which the same Applicant filed on Jan. 28, 1981 and is assumed included herein as reference, and the French Patent No. 2536965, filed on Dec. 2, 1982, are thus known; however, in said patents a problem is observed which is due to the convoluted path of the cable, which complicates the construction of the boot or requires the use of complicated and expensive adjustment mechanisms which also increase the weight of the boot.
Said known types of devices furthermore impose a pressure on the foot which is often constant both during forward and backward flexing and during rest; in practice, instead, greater pressure on the foot is required during forward flexing than during extension or rest.
Finally, during forward flexing the shell and quarters splay, especially in the ankle region; this splaying entails a reduction in the retention of the foot in the boot and thus less sensitivity in the driving of the ski.